Experimental study of gamma-ray attenuation capability of B2O3-ZnO-Na2O-Fe2O3 glass system

In the present work, a glass system with developed composition consisting of B2O3, ZnO, Na2O and Fe2O3 samples has been investigated. Glass samples were prepared using the melt quenching method and the density of the system was measured using Archimedes’ principle. Spectroscopic analysis using a gamma source and a high-purity germanium detector at four energies of 0.0595, 0.6617, 1.173, and 1.333 MeV emitted from Am-241, Cs-137, and Co-60 were used to determine the attenuation parameters of present glass composites. The sample containing 45 B2O3 + 10 Na2O + 40 ZnO + 5 Fe2O3 (coded BNZF-4) had the highest mass attenuation coefficient (MAC) value at all the energies discussed compared to the other composites. Whoever, the BNZF-1 sample had the lowest value at all ranges of energies. The transmission factors (TF, %) of the manufactured samples were calculated, at 0.0595 MeV (TF, %) values are 32.6429 and 6.4612 for samples BNZF-1 and BNZF-4, respectively. The statistical results demonstrated significantly better to increase the ZnO concentration in the sample, where the percentage of zinc oxide inside the prepared glass samples has the following direction BNZF -4 > BNZF -3 > BNZF -2 > BNZF -1. The significance of this study is that transparent, environmentally harmless glass composites with relatively high density have been prepared that can be used as shielding materials against gamma rays, especially at low energies.

occasionally required because it can crack easily and lose moisture when exposed to radiation for an extended period 8,9 .Glasses by adding metallic oxides to their formulation, are capable of functioning as radiation shielding materials.Since their high density raises the density of the glass materials, which usually corresponds to higher shielding properties, heavy metal oxides are usually among the most efficient [10][11][12][13][14] .Moreover, well-known techniques like melt quenching are applicable to create glasses.Because glasses are inexpensive to manufacture, scientists are more inclined to employ them as alternative components for materials that need radiation shielding 15 .
When manufacturing our glass materials, a few factors will be taken into consideration.These include the need for a large mass density as well as excellent transparency to the visible portion of the electromagnetic range to be able to provide beneficial shielding properties and guarantee a notably significant interaction probability between the glass and photons.Consequently, this elevated contact probability means that the energy of ionizing rays will be much reduced and the rays' capacity to pass through glass will be eliminated 15,16 .To improve radiation shielding, one of the strategies is to increase the glass density.It was reported that, glasses based on borate have low viscosity, great mechanical strength, short glass transition temperature, high chemical durability, and clear transparency.They are also cost-effective materials.Owing to these characteristics, glasses based on borate have gained attention for a wide range of uses, such as biomedical, shielding, industrial, and several other uses [17][18][19] .By adding metal oxides as network modifiers such as ZnO, Na 2 O, Fe 2 O 3 , borate glass can be tested for its radiation shielding properties 20 .Borate-based glasses are gaining a lot of attention as radiation shielding materials and considered a hot topic in the discipline of radiation protection safety.Glasses made of borate could have superior shielding properties as their density could be adjusted.Using heavy-duty rare earth oxides and heavy earth oxide metal oxides in glass samples are a simple way to increase glass density [21][22][23] .
In this work, our goal was to manufacture non-toxic and cost-effective glass samples of various compositions using a melt quenching procedure (85-x) B 2 O 3 + 10 Na 2 O + (x)ZnO + 5 Fe 2 O 3 , where x = 10, 20, 30 and 40 wt %.It is also an attempt to mitigate the harmful effects of radiation on humans and the environment and ensure the benefit of ionizing radiation in the long term without exposure to serious harm.

Glass manufacturing
To prepare the glass samples under investigation, some oxides were used, such as ZnO, Na 2 O, Fe 2 O 3 , and B 2 O 3 .Four samples of zinc sodium borate glasses were manufactured with different ratios among them as shown in Table .1 and the ratio were variable between B 2 O 3 and ZnO and constant for Na 2 O, Fe 2 O 3 .The samples were Manufactured according to the annealing technique, the material has been mixed perfectly well and conveniently and placed in a crucible of aluminum and then entered an electric oven at a constant temperature of 950 Celsius for a full 60 min.The other stage is to pour the mixture of molten glass into stainless-steel mold and put it in a separate electric oven at a temperature of 300 for almost 180 min to eliminate internal stresses.
The density of each sample is an important parameter in our work.So, to precisely determine the density of the six samples, we used a very simple and correct method of calculating the density of each sample.The following equation, which uses Archimedes' is used to calculate the density of the manufactured glasses, uses the (W a ) and (W L ) values as symbols for the weight of the glasses in liquid and air.Correspondingly, when utilizing water as an immersing liquid, the ρ L value represents the density of the immersed liquid, which is taken as 1 g/cm 324,25 .

Experimental procedures
The ionizing γ-ray sources Am-241, Co-60, and Cs-137 were identified using an HPGe (high-purity germanium semiconductor detector) with a 24% relative efficiency in this research.The energy range covered by these sources is 60 to 1333 keV.The glass sample was inserted at an appropriate location between the gamma source and the HPGe, as shown in Fig. 1.It displays the experimental setup diagram of attenuation factor calculations., With a lead collimator positioned between the gamma source and the HPGe-detector, the measurements were carried out using the narrow beam technique.The count rate was measured in the case of the sample (A) and in its absence (A 0 ), and those results were recorded Enabling us to identify linear attenuation coefficient (cm −1 ) as well as some important parameters in our work [26][27][28] (1) Chemical composition of the fabricated samples and their density (g/cm 3 ).where x is the glasses sample thickness, depending on I and Io calculations, the other essential shielding-related parameters, such as the radiation protection efficiency (RPE %), half-value thickness (Δ 0.5 , cm), and lead's equivalent thickness (Δ eq , cm), can be expressed using the following formulae [29][30][31] .

Result and Discussion:
Table 1 lists the names, densities, and chemical constituents for each chosen glass system.Table 2 shows the results of linear attenuation coefficients, LAC, at certain gamma energies viz., 0.0595, 0.06617, 1.173 and 1.333 MeV acquired with the experimental and theoretical methods.Experiments were performed with the HPGe detector.The renowned XCOM programme was used to confirm the results that were so acquired.The LAC data were also further utilized to compute additional shielding parameters namely mass attenuation coefficient (MAC), half value layer (HVL), mean free path (MFP), tenth value layer (TVL) and radiation protection efficiency (RPE).
(3)  www.nature.com/scientificreports/Additionally, an assessment of the manufactured glass materials' radiation shielding effectiveness (RSE) and transmission factor (TF %), have been determined.Table 2 presents the relative deviations of LAC values for glass samples obtained from XCOM programme and experiments.It is seen that the relative differences between the XCOM programme and the LAC values obtained from trials are negligible.For example, the theoretical value of 1.1195 validates the experimental value of 1.0923 for BNZF-1 glass at low energy of 0.05595 MeV.Additionally, the XCOM value of 0.1482 confirms the experimental value of 0.1492 for the same glass system at higher energy (1.333 MeV).For the glass samples under investigation, the range of experimental and theoretical deviations is from −6.67 to 6.09. Figure 2 illustrates how the LAC values of the chosen glass samples varied across the photon energy range of 0.0595 MeV to 1.333 MeV.It is clear from this that LAC is dependent upon the chemical composition of the samples as well as the incoming photon energy.The sample BNZF-4 exhibits higher values of LAC than the others because it has the largest density and greater weight fraction of B 2 O 3 (Table 1).After a steep decline from 0.0595 to 0.6617 MeV, there is a little variation in LAC values.The likelihood of interaction is determined by the atomic number (Z n ), where the exponent n fluctuates from 4 to 5, and the dominance of the photoelectric effect at lower energy, in which the interaction cross section depends on energy as σ Ph ~ E −7/2 .At intermediate energies, the Compton effect (σ Com ~ E −1 ) predominates.The attenuation levels at these energies were the same in all samples, as indicated by the LAC values.The reason for this is that Compton scattering has a linear dependence on atomic number, Z 32,33 .
The mass attenuation coefficient (MAC) quantifies the average number of interactions between light photons and matter in a certain mass per unit area thickness of the substance under investigation 33 .Figure 3  The half value layer (HVL), tenth value layer (TVL), and mean free path (MFP) variations as a function of the source photon energy are displayed in Figs.4,5 and 6.These are important characteristics that provide the necessary material thicknesses at certain energy and the material's ability to shield.These variables exhibit the exact opposite pattern of variation from LAC, that is, a rising tendency with incident energy.The lowest values of these parameters across all samples are found at 0.0595 MeV.At lower energy, these thicknesses fall into the   www.nature.com/scientificreports/following ranges: 0.253-4.678cm (HVL); 0.365-6.748cm (MFP); and 0.841-15.539cm (TVL).The values of these characteristics were found to increase with the following trend BNZF-4 < BNZF-3 < BNZF-2 < BNZF-1 among the selected samples.This indicates that BNZF-4 is a superior radiation shield among the glasses under investigation.This is explained by the fact that BNZF-4 has the largest density of all the materials under study, which reduces values for HVL, TVL, and MFP and raises the likelihood of interaction.These outcomes are consistent with the earlier research [34][35][36] .Figure 7 depicts variation of transmission factor (TF, %) versus energy for 1 cm thickness for the glasses under investigation.The trend of variations in TF levels is comparable to that of energy.TFs have lower values at lower energies and increase with increased photon energy.Sample BNZF-1 has TF of 32.6429 whereas BNZF-4 has TF value 6.4612 at 0.0595 MeV.At higher energy of 1.333 MeV, BNZF-1 and BNZF-4 glasses have TFs 86.2273 and 83.4024 sequentially.The effectiveness of a shielding material is determined by several parameters, one of the crucial parameters is its radiation protection efficiency, RSE (%) of the investigated glasses as a function of energy have been portrayed in Fig. 8 at 1 cm.An inverse relation is clearly observed between energy and RSE 33 .This declining tendency is brought on by higher energy photons' greater penetrating power, which lessens ability of these glasses to absorb/block incoming radiation.At 0.0595 MeV, BNZF-1 glass has RSE 67.357% and other glasses have RSE in order of 79-93%.This indicates that the glasses under study are very good at attenuating the lower-energy photons.Among the selected glasses, BNZF-4 glass has shown greatest radiation shielding efficiency.
displays the glasses' MAC values; the photon energy extends from 0.0595 to 1.333 MeV.It was found that the components of the glasses have a significant impact on MAC values; MAC values behave in line with B 2 O 3 levels.Other constituents Na 2 O, ZnO and Fe 2 O 3 have same proportions for all the glasses.The MAC is in the following order: BNZF-4 > BNZF-3 > BNZF-2 > BNZF-1.The energy of the incident photons shows a consistent pattern across all glasses in the MACs.For all glasses, MACs show the same trend in the energy of the incident photons, and it has similar behaviour as that of LAC.